/* Flot plugin for rendering pie charts.

Copyright (c) 2007-2014 IOLA and Ole Laursen.
Licensed under the MIT license.

The plugin assumes that each series has a single data value, and that each
value is a positive integer or zero.  Negative numbers don't make sense for a
pie chart, and have unpredictable results.  The values do NOT need to be
passed in as percentages; the plugin will calculate the total and per-slice
percentages internally.

* Created by Brian Medendorp

* Updated with contributions from btburnett3, Anthony Aragues and Xavi Ivars

The plugin supports these options:

	series: {
		pie: {
			show: true/false
			radius: 0-1 for percentage of fullsize, or a specified pixel length, or 'auto'
			innerRadius: 0-1 for percentage of fullsize or a specified pixel length, for creating a donut effect
			startAngle: 0-2 factor of PI used for starting angle (in radians) i.e 3/2 starts at the top, 0 and 2 have the same result
			tilt: 0-1 for percentage to tilt the pie, where 1 is no tilt, and 0 is completely flat (nothing will show)
			offset: {
				top: integer value to move the pie up or down
				left: integer value to move the pie left or right, or 'auto'
			},
			stroke: {
				color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#FFF')
				width: integer pixel width of the stroke
			},
			label: {
				show: true/false, or 'auto'
				formatter:  a user-defined function that modifies the text/style of the label text
				radius: 0-1 for percentage of fullsize, or a specified pixel length
				background: {
					color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#000')
					opacity: 0-1
				},
				threshold: 0-1 for the percentage value at which to hide labels (if they're too small)
			},
			combine: {
				threshold: 0-1 for the percentage value at which to combine slices (if they're too small)
				color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#CCC'), if null, the plugin will automatically use the color of the first slice to be combined
				label: any text value of what the combined slice should be labeled
			}
			highlight: {
				opacity: 0-1
			}
		}
	}

More detail and specific examples can be found in the included HTML file.

*/

define(function(require , exports , module){
	require("flot");
	(function($) {

		// Maximum redraw attempts when fitting labels within the plot

		var REDRAW_ATTEMPTS = 10;

		// Factor by which to shrink the pie when fitting labels within the plot

		var REDRAW_SHRINK = 0.95;

		function init(plot) {

			var canvas = null,
				target = null,
				options = null,
				maxRadius = null,
				centerLeft = null,
				centerTop = null,
				processed = false,
				ctx = null;

			// interactive variables

			var highlights = [];

			// add hook to determine if pie plugin in enabled, and then perform necessary operations

			plot.hooks.processOptions.push(function(plot, options) {
				if (options.series.pie.show) {

					options.grid.show = false;

					// set labels.show

					if (options.series.pie.label.show == "auto") {
						if (options.legend.show) {
							options.series.pie.label.show = false;
						} else {
							options.series.pie.label.show = true;
						}
					}

					// set radius

					if (options.series.pie.radius == "auto") {
						if (options.series.pie.label.show) {
							options.series.pie.radius = 3/4;
						} else {
							options.series.pie.radius = 1;
						}
					}

					// ensure sane tilt

					if (options.series.pie.tilt > 1) {
						options.series.pie.tilt = 1;
					} else if (options.series.pie.tilt < 0) {
						options.series.pie.tilt = 0;
					}
				}
			});

			plot.hooks.bindEvents.push(function(plot, eventHolder) {
				var options = plot.getOptions();
				if (options.series.pie.show) {
					if (options.grid.hoverable) {
						eventHolder.unbind("mousemove").mousemove(onMouseMove);
					}
					if (options.grid.clickable) {
						eventHolder.unbind("click").click(onClick);
					}
				}
			});

			plot.hooks.processDatapoints.push(function(plot, series, data, datapoints) {
				var options = plot.getOptions();
				if (options.series.pie.show) {
					processDatapoints(plot, series, data, datapoints);
				}
			});

			plot.hooks.drawOverlay.push(function(plot, octx) {
				var options = plot.getOptions();
				if (options.series.pie.show) {
					drawOverlay(plot, octx);
				}
			});

			plot.hooks.draw.push(function(plot, newCtx) {
				var options = plot.getOptions();
				if (options.series.pie.show) {
					draw(plot, newCtx);
				}
			});

			function processDatapoints(plot, series, datapoints) {
				if (!processed)	{
					processed = true;
					canvas = plot.getCanvas();
					target = $(canvas).parent();
					options = plot.getOptions();
					plot.setData(combine(plot.getData()));
				}
			}

			function combine(data) {

				var total = 0,
					combined = 0,
					numCombined = 0,
					color = options.series.pie.combine.color,
					newdata = [];

				// Fix up the raw data from Flot, ensuring the data is numeric

				for (var i = 0; i < data.length; ++i) {

					var value = data[i].data;

					// If the data is an array, we'll assume that it's a standard
					// Flot x-y pair, and are concerned only with the second value.

					// Note how we use the original array, rather than creating a
					// new one; this is more efficient and preserves any extra data
					// that the user may have stored in higher indexes.

					if ($.isArray(value) && value.length == 1) {
	    				value = value[0];
					}

					if ($.isArray(value)) {
						// Equivalent to $.isNumeric() but compatible with jQuery < 1.7
						if (!isNaN(parseFloat(value[1])) && isFinite(value[1])) {
							value[1] = +value[1];
						} else {
							value[1] = 0;
						}
					} else if (!isNaN(parseFloat(value)) && isFinite(value)) {
						value = [1, +value];
					} else {
						value = [1, 0];
					}

					data[i].data = [value];
				}

				// Sum up all the slices, so we can calculate percentages for each

				for (var i = 0; i < data.length; ++i) {
					total += data[i].data[0][1];
				}

				// Count the number of slices with percentages below the combine
				// threshold; if it turns out to be just one, we won't combine.

				for (var i = 0; i < data.length; ++i) {
					var value = data[i].data[0][1];
					if (value / total <= options.series.pie.combine.threshold) {
						combined += value;
						numCombined++;
						if (!color) {
							color = data[i].color;
						}
					}
				}

				for (var i = 0; i < data.length; ++i) {
					var value = data[i].data[0][1];
					if (numCombined < 2 || value / total > options.series.pie.combine.threshold) {
						newdata.push(
							$.extend(data[i], {     /* extend to allow keeping all other original data values
							                           and using them e.g. in labelFormatter. */
								data: [[1, value]],
								color: data[i].color,
								label: data[i].label,
								angle: value * Math.PI * 2 / total,
								percent: value / (total / 100)
							})
						);
					}
				}

				if (numCombined > 1) {
					newdata.push({
						data: [[1, combined]],
						color: color,
						label: options.series.pie.combine.label,
						angle: combined * Math.PI * 2 / total,
						percent: combined / (total / 100)
					});
				}

				return newdata;
			}

			function draw(plot, newCtx) {

				if (!target) {
					return; // if no series were passed
				}

				var canvasWidth = plot.getPlaceholder().width(),
					canvasHeight = plot.getPlaceholder().height(),
					legendWidth = target.children().filter(".legend").children().width() || 0;

				ctx = newCtx;

				// WARNING: HACK! REWRITE THIS CODE AS SOON AS POSSIBLE!

				// When combining smaller slices into an 'other' slice, we need to
				// add a new series.  Since Flot gives plugins no way to modify the
				// list of series, the pie plugin uses a hack where the first call
				// to processDatapoints results in a call to setData with the new
				// list of series, then subsequent processDatapoints do nothing.

				// The plugin-global 'processed' flag is used to control this hack;
				// it starts out false, and is set to true after the first call to
				// processDatapoints.

				// Unfortunately this turns future setData calls into no-ops; they
				// call processDatapoints, the flag is true, and nothing happens.

				// To fix this we'll set the flag back to false here in draw, when
				// all series have been processed, so the next sequence of calls to
				// processDatapoints once again starts out with a slice-combine.
				// This is really a hack; in 0.9 we need to give plugins a proper
				// way to modify series before any processing begins.

				processed = false;

				// calculate maximum radius and center point

				maxRadius =  Math.min(canvasWidth, canvasHeight / options.series.pie.tilt) / 2;
				centerTop = canvasHeight / 2 + options.series.pie.offset.top;
				centerLeft = canvasWidth / 2;

				if (options.series.pie.offset.left == "auto") {
					if (options.legend.position.match("w")) {
						centerLeft += legendWidth / 2;
					} else {
						centerLeft -= legendWidth / 2;
					}
					if (centerLeft < maxRadius) {
						centerLeft = maxRadius;
					} else if (centerLeft > canvasWidth - maxRadius) {
						centerLeft = canvasWidth - maxRadius;
					}
				} else {
					centerLeft += options.series.pie.offset.left;
				}

				var slices = plot.getData(),
					attempts = 0;

				// Keep shrinking the pie's radius until drawPie returns true,
				// indicating that all the labels fit, or we try too many times.

				do {
					if (attempts > 0) {
						maxRadius *= REDRAW_SHRINK;
					}
					attempts += 1;
					clear();
					if (options.series.pie.tilt <= 0.8) {
						drawShadow();
					}
				} while (!drawPie() && attempts < REDRAW_ATTEMPTS)

				if (attempts >= REDRAW_ATTEMPTS) {
					clear();
					target.prepend("<div class='error'>Could not draw pie with labels contained inside canvas</div>");
				}

				if (plot.setSeries && plot.insertLegend) {
					plot.setSeries(slices);
					plot.insertLegend();
				}

				// we're actually done at this point, just defining internal functions at this point

				function clear() {
					ctx.clearRect(0, 0, canvasWidth, canvasHeight);
					target.children().filter(".pieLabel, .pieLabelBackground").remove();
				}

				function drawShadow() {

					var shadowLeft = options.series.pie.shadow.left;
					var shadowTop = options.series.pie.shadow.top;
					var edge = 10;
					var alpha = options.series.pie.shadow.alpha;
					var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

					if (radius >= canvasWidth / 2 - shadowLeft || radius * options.series.pie.tilt >= canvasHeight / 2 - shadowTop || radius <= edge) {
						return;	// shadow would be outside canvas, so don't draw it
					}

					ctx.save();
					ctx.translate(shadowLeft,shadowTop);
					ctx.globalAlpha = alpha;
					ctx.fillStyle = "#000";

					// center and rotate to starting position

					ctx.translate(centerLeft,centerTop);
					ctx.scale(1, options.series.pie.tilt);

					//radius -= edge;

					for (var i = 1; i <= edge; i++) {
						ctx.beginPath();
						ctx.arc(0, 0, radius, 0, Math.PI * 2, false);
						ctx.fill();
						radius -= i;
					}

					ctx.restore();
				}

				function drawPie() {

					var startAngle = Math.PI * options.series.pie.startAngle;
					var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

					// center and rotate to starting position

					ctx.save();
					ctx.translate(centerLeft,centerTop);
					ctx.scale(1, options.series.pie.tilt);
					//ctx.rotate(startAngle); // start at top; -- This doesn't work properly in Opera

					// draw slices

					ctx.save();
					var currentAngle = startAngle;
					for (var i = 0; i < slices.length; ++i) {
						slices[i].startAngle = currentAngle;
						drawSlice(slices[i].angle, slices[i].color, true);
					}
					ctx.restore();

					// draw slice outlines

					if (options.series.pie.stroke.width > 0) {
						ctx.save();
						ctx.lineWidth = options.series.pie.stroke.width;
						currentAngle = startAngle;
						for (var i = 0; i < slices.length; ++i) {
							drawSlice(slices[i].angle, options.series.pie.stroke.color, false);
						}
						ctx.restore();
					}

					// draw donut hole

					drawDonutHole(ctx);

					ctx.restore();

					// Draw the labels, returning true if they fit within the plot

					if (options.series.pie.label.show) {
						return drawLabels();
					} else return true;

					function drawSlice(angle, color, fill) {

						if (angle <= 0 || isNaN(angle)) {
							return;
						}

						if (fill) {
							ctx.fillStyle = color;
						} else {
							ctx.strokeStyle = color;
							ctx.lineJoin = "round";
						}

						ctx.beginPath();
						if (Math.abs(angle - Math.PI * 2) > 0.000000001) {
							ctx.moveTo(0, 0); // Center of the pie
						}

						//ctx.arc(0, 0, radius, 0, angle, false); // This doesn't work properly in Opera
						ctx.arc(0, 0, radius,currentAngle, currentAngle + angle / 2, false);
						ctx.arc(0, 0, radius,currentAngle + angle / 2, currentAngle + angle, false);
						ctx.closePath();
						//ctx.rotate(angle); // This doesn't work properly in Opera
						currentAngle += angle;

						if (fill) {
							ctx.fill();
						} else {
							ctx.stroke();
						}
					}

					function drawLabels() {

						var currentAngle = startAngle;
						var radius = options.series.pie.label.radius > 1 ? options.series.pie.label.radius : maxRadius * options.series.pie.label.radius;

						for (var i = 0; i < slices.length; ++i) {
							if (slices[i].percent >= options.series.pie.label.threshold * 100) {
								if (!drawLabel(slices[i], currentAngle, i)) {
									return false;
								}
							}
							currentAngle += slices[i].angle;
						}

						return true;

						function drawLabel(slice, startAngle, index) {

							if (slice.data[0][1] == 0) {
								return true;
							}

							// format label text

							var lf = options.legend.labelFormatter, text, plf = options.series.pie.label.formatter;

							if (lf) {
								text = lf(slice.label, slice);
							} else {
								text = slice.label;
							}

							if (plf) {
								text = plf(text, slice);
							}

							var halfAngle = ((startAngle + slice.angle) + startAngle) / 2;
							var x = centerLeft + Math.round(Math.cos(halfAngle) * radius);
							var y = centerTop + Math.round(Math.sin(halfAngle) * radius) * options.series.pie.tilt;

							var html = "<span class='pieLabel' id='pieLabel" + index + "' style='position:absolute;top:" + y + "px;left:" + x + "px;'>" + text + "</span>";
							target.append(html);

							var label = target.children("#pieLabel" + index);
							var labelTop = (y - label.height() / 2);
							var labelLeft = (x - label.width() / 2);

							label.css("top", labelTop);
							label.css("left", labelLeft);

							// check to make sure that the label is not outside the canvas

							if (0 - labelTop > 0 || 0 - labelLeft > 0 || canvasHeight - (labelTop + label.height()) < 0 || canvasWidth - (labelLeft + label.width()) < 0) {
								return false;
							}

							if (options.series.pie.label.background.opacity != 0) {

								// put in the transparent background separately to avoid blended labels and label boxes

								var c = options.series.pie.label.background.color;

								if (c == null) {
									c = slice.color;
								}

								var pos = "top:" + labelTop + "px;left:" + labelLeft + "px;";
								$("<div class='pieLabelBackground' style='position:absolute;width:" + label.width() + "px;height:" + label.height() + "px;" + pos + "background-color:" + c + ";'></div>")
									.css("opacity", options.series.pie.label.background.opacity)
									.insertBefore(label);
							}

							return true;
						} // end individual label function
					} // end drawLabels function
				} // end drawPie function
			} // end draw function

			// Placed here because it needs to be accessed from multiple locations

			function drawDonutHole(layer) {
				if (options.series.pie.innerRadius > 0) {

					// subtract the center

					layer.save();
					var innerRadius = options.series.pie.innerRadius > 1 ? options.series.pie.innerRadius : maxRadius * options.series.pie.innerRadius;
					layer.globalCompositeOperation = "destination-out"; // this does not work with excanvas, but it will fall back to using the stroke color
					layer.beginPath();
					layer.fillStyle = options.series.pie.stroke.color;
					layer.arc(0, 0, innerRadius, 0, Math.PI * 2, false);
					layer.fill();
					layer.closePath();
					layer.restore();

					// add inner stroke

					layer.save();
					layer.beginPath();
					layer.strokeStyle = options.series.pie.stroke.color;
					layer.arc(0, 0, innerRadius, 0, Math.PI * 2, false);
					layer.stroke();
					layer.closePath();
					layer.restore();

					// TODO: add extra shadow inside hole (with a mask) if the pie is tilted.
				}
			}

			//-- Additional Interactive related functions --

			function isPointInPoly(poly, pt) {
				for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)
					((poly[i][1] <= pt[1] && pt[1] < poly[j][1]) || (poly[j][1] <= pt[1] && pt[1]< poly[i][1]))
					&& (pt[0] < (poly[j][0] - poly[i][0]) * (pt[1] - poly[i][1]) / (poly[j][1] - poly[i][1]) + poly[i][0])
					&& (c = !c);
				return c;
			}

			function findNearbySlice(mouseX, mouseY) {

				var slices = plot.getData(),
					options = plot.getOptions(),
					radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius,
					x, y;

				for (var i = 0; i < slices.length; ++i) {

					var s = slices[i];

					if (s.pie.show) {

						ctx.save();
						ctx.beginPath();
						ctx.moveTo(0, 0); // Center of the pie
						//ctx.scale(1, options.series.pie.tilt);	// this actually seems to break everything when here.
						ctx.arc(0, 0, radius, s.startAngle, s.startAngle + s.angle / 2, false);
						ctx.arc(0, 0, radius, s.startAngle + s.angle / 2, s.startAngle + s.angle, false);
						ctx.closePath();
						x = mouseX - centerLeft;
						y = mouseY - centerTop;

						if (ctx.isPointInPath) {
							if (ctx.isPointInPath(mouseX - centerLeft, mouseY - centerTop)) {
								ctx.restore();
								return {
									datapoint: [s.percent, s.data],
									dataIndex: 0,
									series: s,
									seriesIndex: i
								};
							}
						} else {

							// excanvas for IE doesn;t support isPointInPath, this is a workaround.

							var p1X = radius * Math.cos(s.startAngle),
								p1Y = radius * Math.sin(s.startAngle),
								p2X = radius * Math.cos(s.startAngle + s.angle / 4),
								p2Y = radius * Math.sin(s.startAngle + s.angle / 4),
								p3X = radius * Math.cos(s.startAngle + s.angle / 2),
								p3Y = radius * Math.sin(s.startAngle + s.angle / 2),
								p4X = radius * Math.cos(s.startAngle + s.angle / 1.5),
								p4Y = radius * Math.sin(s.startAngle + s.angle / 1.5),
								p5X = radius * Math.cos(s.startAngle + s.angle),
								p5Y = radius * Math.sin(s.startAngle + s.angle),
								arrPoly = [[0, 0], [p1X, p1Y], [p2X, p2Y], [p3X, p3Y], [p4X, p4Y], [p5X, p5Y]],
								arrPoint = [x, y];

							// TODO: perhaps do some mathmatical trickery here with the Y-coordinate to compensate for pie tilt?

							if (isPointInPoly(arrPoly, arrPoint)) {
								ctx.restore();
								return {
									datapoint: [s.percent, s.data],
									dataIndex: 0,
									series: s,
									seriesIndex: i
								};
							}
						}

						ctx.restore();
					}
				}

				return null;
			}

			function onMouseMove(e) {
				triggerClickHoverEvent("plothover", e);
			}

			function onClick(e) {
				triggerClickHoverEvent("plotclick", e);
			}

			// trigger click or hover event (they send the same parameters so we share their code)

			function triggerClickHoverEvent(eventname, e) {

				var offset = plot.offset();
				var canvasX = parseInt(e.pageX - offset.left);
				var canvasY =  parseInt(e.pageY - offset.top);
				var item = findNearbySlice(canvasX, canvasY);

				if (options.grid.autoHighlight) {

					// clear auto-highlights

					for (var i = 0; i < highlights.length; ++i) {
						var h = highlights[i];
						if (h.auto == eventname && !(item && h.series == item.series)) {
							unhighlight(h.series);
						}
					}
				}

				// highlight the slice

				if (item) {
					highlight(item.series, eventname);
				}

				// trigger any hover bind events

				var pos = { pageX: e.pageX, pageY: e.pageY };
				target.trigger(eventname, [pos, item]);
			}

			function highlight(s, auto) {
				//if (typeof s == "number") {
				//	s = series[s];
				//}

				var i = indexOfHighlight(s);

				if (i == -1) {
					highlights.push({ series: s, auto: auto });
					plot.triggerRedrawOverlay();
				} else if (!auto) {
					highlights[i].auto = false;
				}
			}

			function unhighlight(s) {
				if (s == null) {
					highlights = [];
					plot.triggerRedrawOverlay();
				}

				//if (typeof s == "number") {
				//	s = series[s];
				//}

				var i = indexOfHighlight(s);

				if (i != -1) {
					highlights.splice(i, 1);
					plot.triggerRedrawOverlay();
				}
			}

			function indexOfHighlight(s) {
				for (var i = 0; i < highlights.length; ++i) {
					var h = highlights[i];
					if (h.series == s)
						return i;
				}
				return -1;
			}

			function drawOverlay(plot, octx) {

				var options = plot.getOptions();

				var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

				octx.save();
				octx.translate(centerLeft, centerTop);
				octx.scale(1, options.series.pie.tilt);

				for (var i = 0; i < highlights.length; ++i) {
					drawHighlight(highlights[i].series);
				}

				drawDonutHole(octx);

				octx.restore();

				function drawHighlight(series) {

					if (series.angle <= 0 || isNaN(series.angle)) {
						return;
					}

					//octx.fillStyle = parseColor(options.series.pie.highlight.color).scale(null, null, null, options.series.pie.highlight.opacity).toString();
					octx.fillStyle = "rgba(255, 255, 255, " + options.series.pie.highlight.opacity + ")"; // this is temporary until we have access to parseColor
					octx.beginPath();
					if (Math.abs(series.angle - Math.PI * 2) > 0.000000001) {
						octx.moveTo(0, 0); // Center of the pie
					}
					octx.arc(0, 0, radius, series.startAngle, series.startAngle + series.angle / 2, false);
					octx.arc(0, 0, radius, series.startAngle + series.angle / 2, series.startAngle + series.angle, false);
					octx.closePath();
					octx.fill();
				}
			}
		} // end init (plugin body)

		// define pie specific options and their default values

		var options = {
			series: {
				pie: {
					show: false,
					radius: "auto",	// actual radius of the visible pie (based on full calculated radius if <=1, or hard pixel value)
					innerRadius: 0, /* for donut */
					startAngle: 3/2,
					tilt: 1,
					shadow: {
						left: 5,	// shadow left offset
						top: 15,	// shadow top offset
						alpha: 0.02	// shadow alpha
					},
					offset: {
						top: 0,
						left: "auto"
					},
					stroke: {
						color: "#fff",
						width: 1
					},
					label: {
						show: "auto",
						formatter: function(label, slice) {
							return "<div style='font-size:x-small;text-align:center;padding:2px;color:" + slice.color + ";'>" + label + "<br/>" + Math.round(slice.percent) + "%</div>";
						},	// formatter function
						radius: 1,	// radius at which to place the labels (based on full calculated radius if <=1, or hard pixel value)
						background: {
							color: null,
							opacity: 0
						},
						threshold: 0	// percentage at which to hide the label (i.e. the slice is too narrow)
					},
					combine: {
						threshold: -1,	// percentage at which to combine little slices into one larger slice
						color: null,	// color to give the new slice (auto-generated if null)
						label: "Other"	// label to give the new slice
					},
					highlight: {
						//color: "#fff",		// will add this functionality once parseColor is available
						opacity: 0.5
					}
				}
			}
		};

		$.plot.plugins.push({
			init: init,
			options: options,
			name: "pie",
			version: "1.1"
		}); 

	})(jQuery);
})

